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The Journal of Endocrinology Jun 2024Biallelic variants of steroidogenic acute regulatory protein (STAR/STARD1) may cause primary adrenal insufficiency and 46,XY disorder of sex development. STAR plays a... (Review)
Review
Biallelic variants of steroidogenic acute regulatory protein (STAR/STARD1) may cause primary adrenal insufficiency and 46,XY disorder of sex development. STAR plays a pivotal role in transporting cholesterol into mitochondria where cholesterol serves as essential substrate for initiating steroid biosynthesis by its conversion to pregnenolone. Generally, loss-of-function mutations of STAR cause the classic form of lipoid Congenital Adrenal Hyperplasia (LCAH) where steroidogenesis of the adrenal cortex and the gonads is severely affected. By contrast, partial activity of STAR causes a less severe phenotype, the non-classic LCAH, which is characterized by later onset and initial manifestation with isolated adrenal insufficiency only. Disease causing STAR variants are very rare. Numerous variants of all types have been described worldwide. Prevailing variants have been reported from Japan and Korea and in some population clusters where STAR is more common. Genotype-phenotype correlation is pretty good for STAR variants. While the exact mechanisms of cholesterol transport into mitochondria for steroidogenesis are still under investigation, the important role of STAR in this process is evident by inactivating STAR variants causing LCAH. The mechanism of disease with STAR deficiency is best described by a two hit model: The first hit relates to impaired cholesterol import into mitochondria and thus lack of substrate for all steroid hormone biosynthesis. The second hit then relates to massive cytoplasmic lipid overload (evidenced by typically enlarged and fatty adrenal glands) leading to cell death and organ destruction. This review summarizes phenotype and genotype characteristics of human STAR variants found through the ClinVar database.
PubMed: 38913505
DOI: 10.1530/JOE-24-0078 -
Basic & Clinical Pharmacology &... Jun 2024Human pregnane X receptor (PXR) is critical for regulating the expression of key drug-metabolizing enzymes such as CYP3A and CYP2C. Our recent study revealed that...
Human pregnane X receptor (PXR) is critical for regulating the expression of key drug-metabolizing enzymes such as CYP3A and CYP2C. Our recent study revealed that treatment with rodent-specific PXR agonist pregnenolone-16α-carbonitrile (PCN) significantly induced hepatomegaly and promoted liver regeneration after two-thirds partial hepatectomy (PHx) in mice. However, it remains unclear whether PXR activation induces hepatomegaly and liver regeneration and simultaneously promotes metabolic function of the liver. Here, we investigated the metabolism activity of CYP1A2, CYP3A1/2 and CYP2C6/11 during PXR activation-induced liver enlargement and regeneration in rats after cocktail dosing of CYP probe drugs. For PCN-induced hepatomegaly, a notable increase in the metabolic activity of CYP3A1/2 and CYP2C6/11, as evidenced by the plasma exposure of probe substrates and the AUC ratios of the characteristic metabolites to its corresponding probe substrates. The metabolic activity of CYP1A2, CYP3A1/2 and CYP2C6/11 decreased significantly after PHx. However, PCN treatment obviously enhanced the metabolic activity of CYP2C6/11 and CYP3A1/2 in PHx rats. Furthermore, the protein expression levels of CYP3A1/2 and CYP2C6/11 in liver were up-regulated. Taken together, this study demonstrates that PXR activation not only induces hepatomegaly and liver regeneration in rats, but also promotes the protein expression and metabolic activity of the PXR downstream metabolizing enzymes such as CYP3A1/2 and CYP2C6/11 in the body.
PubMed: 38887973
DOI: 10.1111/bcpt.14041 -
Reproductive Toxicology (Elmsford, N.Y.) Jun 2024Ketoconazole (KTZ) is widely used as a fungicide, but it is also known to target steroid hormone formation which may affect female reproductive health. Our study aims to...
Ketoconazole (KTZ) is widely used as a fungicide, but it is also known to target steroid hormone formation which may affect female reproductive health. Our study aims to investigate the effects of KTZ on in vitro matured bovine cumulus-oocyte complexes (COCs), as a model for female reproductive toxicity. Cumulus cells of in vitro maturing COCs produce progesterone and pregnenolone, but exposure to 10 M KTZ effectively blocked the synthesis of these hormones. Exposure to lower concentrations of KTZ (i.e. 10 M and 10 M) had no such effect on steroidogenesis compared to the 0.1 % v/v DMSO vehicle control. Classical parameters of in vitro COC maturation, such as oocyte nuclear maturation to the metaphase II stage and expansion of the cumulus investment, were not affected by any KTZ concentration tested. Apoptosis and necrosis levels were also not altered in cumulus cells or oocytes exposed to KTZ. Moreover, oocytes exposed to KTZ during maturation showed normal cleavage and early embryo development up to day 8 post fertilization; albeit a statistically significant decrease was observed in day 8 blastocysts produced from oocytes exposed to the lowest concentration of 10 M KTZ. When unexposed mature oocytes were fertilized, followed by embryo culture for 8 days under KTZ exposure, no adverse effects in embryo cleavage and blastocyst formation were observed. In conclusion, KTZ has no major impact on in vitro bovine oocyte maturation and blastocyst formation in our study, even at concentrations blocking steroidogenesis.
PubMed: 38876429
DOI: 10.1016/j.reprotox.2024.108637 -
IScience Jun 2024Multiple metabolic events occur in mitochondria. Mitochondrial protein translocation from the cytoplasm across compartments depends on the amino acid sequence within the...
Multiple metabolic events occur in mitochondria. Mitochondrial protein translocation from the cytoplasm across compartments depends on the amino acid sequence within the precursor. At the mitochondria associated-ER membrane, misfolding of a mitochondrial targeted protein prior to import ablates metabolism. CYP11A1, cytochrome P450 cholesterol side chain cleavage enzyme (SCC), is imported from the cytoplasm to mitochondrial matrix catalyzing cholesterol to pregnenolone, an essential step for metabolic processes and mammalian survival. Multiple steps regulate the availability of an actively folded SCC; however, the mechanism is unknown. We identified that a dry molten globule state of SCC exists in the matrix by capturing intermediate protein folding steps dictated by its C-terminus. The intermediate dry molten globule state in the mitochondrial matrix of living cells is stable with a limited network of interaction and is inactive. The dry molten globule is activated with hydrogen ions availability, triggering cleavage of cholesterol sidechain, and initiating steroidogenesis.
PubMed: 38868187
DOI: 10.1016/j.isci.2024.110039 -
Genomics Jun 2024The investigation of dwarfing rootstocks for the establishment of high-generation seed orchards is a prospective avenue of research. In this investigation, Pinus...
The investigation of dwarfing rootstocks for the establishment of high-generation seed orchards is a prospective avenue of research. In this investigation, Pinus massoniana, Pinus yunnanensis var. pygmaea (P. pygmaea), and P. elliottii seedlings were used as rootstocks for grafting with P. massoniana scions. Grafting P. massoniana onto P. pygmaea rootstock resulted in observable phenotypic alterations in lateral branches, apical buds, and needle length. Certain characteristic metabolites of rootstocks, such as fatty acyls, pregnenolones, steroids, and steroid derivatives, were found to be highly expressed in scions after grafting. RNA-seq analysis revealed MYB-related, SBP, and bHLH demonstrating a significant positive correlation, while C2H2 and Orphans exhibited negative correlations with the differential intensity of metabolites related to lipids and lipid-like molecules. This study offers valuable insights for the establishment of rootstock breeding programs.
PubMed: 38857814
DOI: 10.1016/j.ygeno.2024.110882 -
European Journal of Medical Genetics Jun 202421-hydroxylase deficiency stands as the most prevalent form of congenital adrenal hyperplasia, primarily resulting from mutations in the CYP21A2 gene. On the other hand,...
21-hydroxylase deficiency stands as the most prevalent form of congenital adrenal hyperplasia, primarily resulting from mutations in the CYP21A2 gene. On the other hand, mutations within the CYP17A1 gene lead to 17α-hydroxylase/17,20-lyase enzyme deficiencies. The scarcity of 17-OH deficiency is noteworthy, accounting for less than 1% of all congenital adrenal hyperplasia cases. The male patient, born from a first-degree cousin marriage, exhibited several symptoms, including left undescended testis, micropenis, penile chord, left sensorineural hearing loss, and gynecomastia. He reported micropenis as a concern at the age of 13.5 years. His hormone profile revealed high levels of serum 17-hydroxyprogesterone, progesterone, and pregnenolone. In this case with a 46 XY karyotype, suspicions arose regarding Cytochrome P450 oxidoreductase deficiency due to ambiguous genitalia and an atypical hormone profile. Analysis unveiled two distinct homozygous and pathogenic variants in the CYP21A2 and CYP17A1 genes. Notably, mineralocorticoid precursors escalated, while cortisol and sex steroid precursors decreased during the high (250 mcg) dose ACTH stimulation test. The mutation c.1169C > G (p.Thr390Arg) in CYP17A1, which is the second documented case in literature, stands out due to its unique set of accompanying features. Mutations occurring in CYP21A2 and CYP17A1 result in complete or partial enzyme deficiencies, and the detection of homozygous mutations in two different enzyme systems within the steroidogenic pathway is noteworthy.
Topics: Humans; Adrenal Hyperplasia, Congenital; Male; Steroid 17-alpha-Hydroxylase; Steroid 21-Hydroxylase; Adolescent; Mutation
PubMed: 38852772
DOI: 10.1016/j.ejmg.2024.104952 -
Physical Chemistry Chemical Physics :... Jun 2024The human steroidogenic cytochrome P450 CYP17A1 catalyzes two types of reactions in the biosynthetic pathway leading from pregnenolone to testosterone and several other...
The human steroidogenic cytochrome P450 CYP17A1 catalyzes two types of reactions in the biosynthetic pathway leading from pregnenolone to testosterone and several other steroid hormones. The first is the hydroxylation of pregnenolone or progesterone to the corresponding 17α-hydroxy steroid, followed by a lyase reaction that converts these 17α-hydroxy intermediates to the androgens dehydroepiandrosterone and androstenedione, respectively. cytochrome (cyt) is known to act as both an effector and electron donor for the lyase oxidations, markedly stimulating the rate of the lyase reaction in its presence relative to the rate in its absence. Extensive sequential backbone H,N and C nuclear magnetic resonance assignments have now been made for oxidized CYP17A1 bound to the prostate cancer drug and inhibitor abiraterone. This is the first eukaryotic P450 for which such assignments are now available. These assignments allow more complete interpretation of the structural perturbations observed upon cyt addition. Possible mechanism(s) for the effector activity of cyt are discussed in light of this new information.
Topics: Steroid 17-alpha-Hydroxylase; Cytochromes b5; Humans; Nuclear Magnetic Resonance, Biomolecular; Protein Binding; Androstenes; Protein Conformation; Oxidation-Reduction; Magnetic Resonance Spectroscopy
PubMed: 38842434
DOI: 10.1039/d4cp01268b -
Molecular and Cellular Endocrinology Jun 2024Adrenarche is a normal developmental event in mid-childhood characterized by increasing adrenal androgen secretion. The role of the classic androgen pathway has been...
CONTEXT
Adrenarche is a normal developmental event in mid-childhood characterized by increasing adrenal androgen secretion. The role of the classic androgen pathway has been well described in adrenarche, but the role of newer active androgens and additional androgen pathways is less clear.
OBJECTIVE
To study the contribution of novel androgens and related steroid biosynthesis pathways to the development of adrenarche, and to identify additional steroid biomarkers of adrenarche.
DESIGN
A longitudinal study of children aged 6-8 years at baseline, followed up at ages 8-10 and 14-16 years. A total of 34 children (20 girls) with clinical and/or biochemical signs of adrenarche (cases) and 24 children (11 girls) without these signs (controls) at age 8-10 years were included. Serum steroid profiling was performed by liquid chromatography high-resolution mass spectrometry.
MAIN OUTCOME MEASURES
Thirty-two steroids compartmentalized in progestagens, gluco- and mineralocorticoid pathways, and four androgen related pathways, including the classic, backdoor, 11-oxy, and 11-oxy backdoor pathways.
RESULTS
The classic and 11-oxy androgen pathways were more active, and serum concentrations of main androgens in the classic (dehydroepiandrosterone, dehydroepiandrosterone sulfate, androstenedione and androsterone) and 11-oxy (11β-hydroxyandrostenedione, 11β-hydroxytestosterone, 11-ketoandrostenedione, and 11-ketotestosterone) pathways were higher in cases at ages 6-8 and 8-10 years. Pregnenolone concentrations at adrenarchal age (8-10 years) and cortisol concentrations at adolescence (14-16 years) were higher in cases. 11β-hydroxyandrosterone and 11-ketoandrosterone tended to be higher in cases with clinical signs compared to cases who had only biochemical evidence of adrenarche, albeit they were detected at low levels. In biomarker analyses, calculated steroid ratios with cortisol, cortisone, or 11-deoxycortisone as dividers were better classifiers for adrenarche than single steroids. Among these ratios, androstenedione/cortisone was the best.
CONCLUSIONS
The classic and 11-oxy androgen pathways are active in adrenarche. Children with earlier timing of adrenarche have higher serum cortisol levels at late pubertal age, suggesting that early adrenarche might have long-term effects on adrenal steroidogenesis by increasing the activity of the glucocorticoid pathway. Future studies should employ comprehensive steroid profiling to define novel classifiers and biomarkers for adrenarche and premature adrenarche.
PubMed: 38838762
DOI: 10.1016/j.mce.2024.112293 -
Journal of Animal Science and... Jun 2024The hypothalamus plays a crucial role in the health and productivity of dairy cows, yet studies on its functionality and its impact on peripheral circulation in these...
BACKGROUND
The hypothalamus plays a crucial role in the health and productivity of dairy cows, yet studies on its functionality and its impact on peripheral circulation in these animals are relatively scarce, particularly regarding dietary interventions. Therefore, our study undertook a comprehensive analysis, incorporating both metabolomics and transcriptomics, to explore the effects of a grain-based diet on the functionality of the hypothalamus, as well as on blood and milk in dairy cows.
RESULTS
The hypothalamic metabolome analysis revealed a significant reduction in prostaglandin E (PGE) level as a prominent response to the grain-based diet introduction. Furthermore, the hypothalamic transcriptome profiling showed a notable upregulation in amino acid metabolism due to the grain-based diet. Conversely, the grain-based diet led to the downregulation of genes involved in the metabolic pathway from lecithin to PGE, including phospholipase A2 (PLA2G4E, PLA2G2A, and PLA2G12B), cyclooxygenase-2 (COX2), and prostaglandin E synthase (PTGES). Additionally, the plasma metabolome analysis indicated a substantial decrease in the level of PGE, along with a decline in adrenal steroid hormones (tetrahydrocortisol and pregnenolone) following the grain-based diet introduction. Analysis of the milk metabolome showed that the grain-based diet significantly increased uric acid level while notably decreasing PGE level. Importantly, PGE was identified as a critical metabolic marker in the hypothalamus, blood, and milk in response to grain intervention. Correlation analysis demonstrated a significant correlation among metabolic alterations in the hypothalamus, blood, and milk following the grain-based diet.
CONCLUSIONS
Our findings suggest a potential link between hypothalamic changes and alterations in peripheral circulation resulting from the introduction of a grain-based diet.
PubMed: 38822422
DOI: 10.1186/s40104-024-01034-3 -
Cellular and Molecular Life Sciences :... May 2024N-methyl-D-aspartate receptors (NMDARs emerging from GRIN genes) are tetrameric receptors that form diverse channel compositions in neurons, typically consisting of two...
N-methyl-D-aspartate receptors (NMDARs emerging from GRIN genes) are tetrameric receptors that form diverse channel compositions in neurons, typically consisting of two GluN1 subunits combined with two GluN2(A-D) subunits. During prenatal stages, the predominant channels are di-heteromers with two GluN1 and two GluN2B subunits due to the high abundance of GluN2B subunits. Postnatally, the expression of GluN2A subunits increases, giving rise to additional subtypes, including GluN2A-containing di-heteromers and tri-heteromers with GluN1, GluN2A, and GluN2B subunits. The latter emerge as the major receptor subtype at mature synapses in the hippocampus. Despite extensive research on purely di-heteromeric receptors containing two identical GRIN variants, the impact of a single variant on the function of other channel forms, notably tri-heteromers, is lagging. In this study, we systematically investigated the effects of two de novo GRIN2B variants (G689C and G689S) in pure, mixed di- and tri-heteromers. Our findings reveal that incorporating a single variant in mixed di-heteromers or tri-heteromers exerts a dominant negative effect on glutamate potency, although 'mixed' channels show improved potency compared to pure variant-containing di-heteromers. We show that a single variant within a receptor complex does not impair the response of all receptor subtypes to the positive allosteric modulator pregnenolone-sulfate (PS), whereas spermine completely fails to potentiate tri-heteromers containing GluN2A and -2B-subunits. We examined PS on primary cultured hippocampal neurons transfected with the variants, and observed a positive impact over current amplitudes and synaptic activity. Together, our study supports previous observations showing that mixed di-heteromers exhibit improved glutamate potency and extend these findings towards the exploration of the effect of Loss-of-Function variants over tri-heteromers. Notably, we provide an initial and crucial demonstration of the beneficial effects of GRIN2B-relevant potentiators on tri-heteromers. Our results underscore the significance of studying how different variants affect distinct receptor subtypes, as these effects cannot be inferred solely from observations made on pure di-heteromers. Overall, this study contributes to ongoing efforts to understand the pathophysiology of GRINopathies and provides insights into potential treatment strategies.
Topics: Receptors, N-Methyl-D-Aspartate; Pregnenolone; Humans; Animals; HEK293 Cells; Hippocampus; Loss of Function Mutation; Protein Multimerization; Neurons; Protein Subunits
PubMed: 38795169
DOI: 10.1007/s00018-024-05243-x